Table 2.

Full-scale Intelligence Quotient scores averaged^a from ages 5 and 8 years according to covariates among mother-child dyads with child race, according to covariates: the HOME study (2003–2006)

	Non-Hispanic Black		Non-Hispanic White
Variable	n	Mean ± SD	n	Mean ± SD
Overall	90	91 ± 13	145	107 ± 12
Maternal age (years)
<25	45	89 ± 15	8	101 ± 14
25 to <35	40	91 ± 11	104	107 ± 12
35+	5	103 ± 13	33	108 ± 13
Maternal education
High school or less	51	88 ± 14	7	98 ± 17
Some college	31	92 ± 13	37	103 ± 13
Completed college	8	102 ± 5.9	101	109 ± 11
Annual income
<$30,000	70	89 ± 14	9	98 ± 19
$30,000 to $75,000	17	95 ± 11	55	104 ± 12
≥$75,000	3	103 ± 6.6	81	110 ± 10
Maternal smokingb
Unexposed	5	96 ± 7.2	66	106 ± 12
Secondhand smoking	40	91 ± 12	71	107 ± 13
Active smoking	45	91 ± 17	8	111 ± 17
Parity
0	29	88 ± 14	73	109 ± 13
1	29	91 ± 13	46	107 ± 10
2+	32	93 ± 13	26	103 ± 12
Prepregnancy BMI (kg/m2)
Normal/underweight: <25	32	88 ± 15	83	108 ± 12
Overweight: ≥25 to <30	23	95 ± 11	38	107 ± 13
Obese: ≥30	35	90 ± 13	24	104 ± 14
Child sex
Male	33	89 ± 13	69	105 ± 13
Female	57	92 ± 14	76	109 ± 12

^aAverage FSIQ values represent the arithmetic mean of repeated child FSIQ scores. In cases where children only had one FSIQ measure, that value was used to represent the mean. Of the full analytic sample (n = 253), n = 169 children had two measures of FSIQ ascertained at 5 and 8 yrs (67%).

^bMaternal smoking during pregnancy estimated based on maternal serum cotinine concentrations during pregnancy. Unexposed smoking exposure defined as having serum cotinine concentrations <0.015 ng/mL, secondhand smoking exposure is defined by serum cotinine concentrations between 0.015 and <3.00 ng/mL, and active smoking includes those with serum cotinine concentrations ≥3.00 ng/mL.